Pre-assembly of thin, flexible workpieces such as found in the garment industry and elsewhere is increasingly important to avoid inaccurate matching of parts and to attain greater productivity. Also, the burden of manually separating and then properly aligning such workpieces is to be shunned if they are to be subsequently joined without loss of productivity and of proper registration. This invention is accordingly directed to providing a method and apparatus for assembly from different stacks of flexible workpieces the individual perforate plies which are to be registered with one another, then uniting them at least temporarily in their registered relation, and lastly stacking the assemblies for further processing.
The invention will probably have primary use in the fabric and garment industries, but it is to be understood that usage of the invention is not thus limited. Also, the particular work joining mechanism herein optionally employed by ways of illustration is advantageous in that it conveniently employs heat for at least temporarily attaching (as by spot welding) the plies together, at least one of the plies being a polyester material; it will be clear, however, that the invention is in many respects not limited to use with the heat or other fastening feature, nor to use in dealing with a polyester ply. Moreover, though specifically illustrated as applied to shirt collar making usage of the invention is not necessarily restricted to use on fabric of particular type or for a particular purpose.
Multi-ply fabric assemblies, herein typified in the making of collars for mens' dress shirts, are commonly difficult to manipulate even when their parts are first registered with each other and, prior to that, the workpieces are not easily separated singly from their respective stacks formed usually by die cutting operations. As commonly known some fabrics are sleazy, some have greater body, and some are clingy while others slide easily; the great variety of their characteristics makes complex the provision of a sufficiently versatile machine for reliably assembling them in uniform predetermined relation. It is appreciated that a mechanized pre-assembly of collar plies, for instance, in precise superposed relation will greatly facilitate subsequent collar finishing operations when the plies are at least temporarily fastened together. The art of making mens' dress shirt collars has hitherto called for a mixture of non-skilled but burdensome operations (such as manually separating, positioning and spreading out each ply) with highly skilled maneuvers involved in maintaining the parts in registry while guiding the assemblage in precise manner relative to a needle to insure that seaming runs exactly a uniform distance from the edge of the three sides of the collar and stops at specified points. Occasionally stitch tacking at spaced points is made to aid an operator in uniformly moving the collar plies but then productivity is reduced by the need thereafter to snip and remove the temporary thread attachment.
In some superficial respects it may be noted that a general resemblance exists between the disclosure of U.S. Pat. No. 3,608,118 issued Sept. 28, 1971 on an application of Frederick J. Rex et al. and the illustrative apparatus herein to be described. An important distinction is that workpiece in the latter are previous necessitating unique positioning technique workpieces in the former the leather work is simply held in the desired position by suction. Accordingly the present invention features novel pneumatic work positioning means associated with each cooperating work transfer mechanism.